Tantipong 2008.

Study characteristics
Methods	Study design: single‐centre RCT with 2 parallel groups Location: Thailand Number of centres: 1 tertiary care university hospital Study period: January 2006 through March 2007 Funding source: Thailand Research Fund and Faculty of Medicine Siriraj Hospital
Participants	Inclusion criteria: eligible patients were adults aged ≧ 18 years who were hospitalised in intensive care units (36 beds) or general medical wards (240 beds) at Siriraj Hospital and who received mechanical ventilation. Exclusion criteria: patients who had pneumonia at enrolment or who had a chlorhexidine allergy Number randomised: 207 Number evaluated: 207 (110 participants received mechanical ventilation for > 48 hours) ‐ Experimental group: n = 102; age: 56.5 ± 20.1; M/F: 50/52; mean APACHE II score: 16.7 ± 7.9 ‐ Control group: n = 105; age: 60.3 ± 19.1; M/F: 51/54; mean APACHE II score: 18.2 ± 8.1 Participants' demographic characteristics between groups did not differ significantly.
Interventions	Comparison: toothbrush + chlorhexidine vs toothbrush + placebo Experimental group (n = 102): received oral care 4 times a day with brushing the teeth, suctioning any oral secretions, and rubbing the oropharyngeal mucosa with 15 mL of a 2% chlorhexidine solution, until their endotracheal tubes were removed. Control group (n = 105): same oral care procedure with normal saline solution
Outcomes	1. Incidence of VAP 2. Number of cases of VAP per 1000 ventilator days 3. Incidence of VAP for participants who received mechanical ventilation for > 2 days 4. Overall mortality 5. Mean days of mechanical ventilation (mean ± SD) 6. Rate of irritation of oral mucosa
Notes	Sample size calculation: estimated that 108 participants required in each group to give 80% power to detect a 50% decrease in VAP with 5% Type 1 error
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"...randomized...by stratified randomization according to sex and hospital location of eligible patient"
Allocation concealment (selection bias)	Unclear risk	Not mentioned and probably not done
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not blinded as chlorhexidine solution had different odour and taste from saline
Blinding of outcome assessment (detection bias) All outcomes	Low risk	The assessors who determined whether a participant developed pneumonia were unaware of the participant's study group assignment.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	All randomised participants included in outcome evaluation but only 53% of participants on ventilators for > 2 days and therefore at risk of VAP
Selective reporting (reporting bias)	Unclear risk	Planned outcome VAP but not all participants at risk and information unclear. Mortality reported
Other bias	Unclear risk	Only 60% of study participants received ventilation in ICU and only 53% of participants received mechanical ventilation for > 48 hours. Likely that nursing care protocols were different in general medical wards compared to ICUs